1. Technical Field
The present invention relates generally to semiconductor devices, and more particularly, to heat dissipation for a heat generating element in a semiconductor device.
2. Related Art
Heat dissipation in semiconductor devices continues to be a challenge as size continually shrinks. One particular element in semiconductor device structures that presents challenges relative to heat dissipation is a precision resistor, which represents an important element in microprocessor technology. For example, precision resistors are used to reduce parasitic capacitance in conventional advanced logic circuits. For technologies at 90 nm and smaller, refractory metal resistors embedded in the back-end-of-the-line (BEOL) (i.e., after first metal) are being used instead of polysilicon or single crystalline resistors due to their better resistance tolerance, lower thermal coefficient of resistance (TCR) and lower parasitic capacitance to transistors which are imbedded in the silicon. Unfortunately, the resistance of precision resistors ranges from about 60 to 100 Ohms/square, which under normal operating currents, generates substantial heat in and near the precision resistor. As a result, the temperature of the surrounding BEOL metallic interconnections also increases. Higher temperatures limit the performance of the precision resistors and degrade the electromigration performance of surrounding metal, which leads to lower maximum currents and increased complexity and cost to produce semiconductor microprocessors. Since no metal is allowed above or below the precision resistors, only heat transmission through typically very poor heat conductive dielectrics is possible.
In view of the foregoing, there is a need in the art for a way to dissipate the heat generation of precision resistors.